Some roof systems provide vegetation growth on a roof of a building or other structure, which roof systems may be referred to as green roof systems. Typical green roof systems include a waterproof membrane applied to the surface of the roof, a layer of soil or other growing medium provided on top of the membrane, and vegetation provided in the soil. The green roof systems may result in lower energy costs for the building, improved roof appearance, noise reduction and increased roof life, and reduction in building's temperature.
Some green roof systems can be used for filtering rain water. The rain water passes through the vegetation of the green roof system and enters a storage area. The water that has passed through the vegetation may not be potable, but may considered as “gray water” to be utilized for non-drinking activities such as for example, shower, toilets, and other cleaning type activities. However, such green roof systems may require a large area for installation and therefore may be difficult to install on buildings that have a limited space. Furthermore, such green roof system may not be configured to take advantage of various natural resources to generate electricity, provide drinking water, and/or provide clean air for the building.
Hence, there is a need for an improved roof system that can be configured to generate electricity, drinking water, and/or provide clean air for the building.